Penny: I think about a lot of things. I think about us getting married, I think about us breaking up. Once in a while, I think about how I didn't leave a note on that Mercedes I dinged in the parking lot last month, but then I have a glass of wine and it passes.

Leonard: Joke all you want, but you think about it.
Penny: Well, tell you one thing, if I ever do get married, no Klingon invitations.
Leonard: Good luck catching a man with that attitude.

Amy: Come on, Sheldon. We can be like Marie Curie and her husband, Pierre, who spent their days working side by side, bathed in the glow of their love and the radium that ultimately killed her. Screw Beauty and the Beast, that's the love story Disney should tell.

Leonard: Where's Howard?
Raj: No hi, Raj? No how are you, Raj? Just straight to where's the other white guy?

Leonard: So, listen, I heard something about him. Can you keep it between us?
Raj: Ooh, gossip. When I first got here, I thought you Americans really gossiped around the water cooler. So I hung out there for, like, a month, but the only gossip I ever heard was about some creepy guy hanging out by the water cooler.

Leonard: Bernadette wants to get a pre-nup.
Raj: Oh, that's a shame, he's gonna be devastated.
Leonard: I never know what to do in these situations. Should I give him a heads-up?
Raj: Hmm. I'm gonna give you the same advice I yell at the TV when the Bachelor's handing out roses. Follow your heart.

Howard: You know what, it's not a big deal. She makes more money than me. She wants to protect her financial interests. It's completely reasonable.
Leonard; Good. That's a healthy attitude.
Howard: Yeah, actually, it's good for both of us. I have assets to protect, too.
Raj: Like what?
Howard: I've got some rare comic books. The Vespa's almost paid off. And Ma and I have a primo double cemetery plot at Mount Sinai right near the guy who played Mr. Roper on Three's Company.
Raj: Mr. Roper's dead? You can't just spring that on a guy.

Sheldon: Those are perfectly clean.
Amy: Sheldon, this beaker used to contain cerebral spinal fluid from an elephant that died of syphilis. If it is, in fact, perfectly clean, drink from it.

Sheldon: 366, 367
Amy: How's it going?
Sheldon: How's counting going? When I was in kindergarten, I recited Pi to a thousand places for the school talent show. I think I got this.
Amy: Great.
Sheldon: Aw, nuts! One

Sheldon: This is preposterous. I think you're giving me these tasks because you're afraid if you give me anything meaningful to do, I'll show you up.
Amy: Really? Is that what you think?
Sheldon: Yes, that's what I think. And I'm super smart, so it's probably true.

Amy: Hey, I've been training in the field of neurobiology for 12 years. You've been here for three hours, and you've spent one of them in the bathroom.
Sheldon: I'm sorry. It takes me a while to get things going on an unfamiliar toilet.

Amy: Sheldon, I've given you the simplest things to do, and you haven't done one of them right.
Sheldon: Maybe that's because I'm not being challenged. It's the same reason Einstein failed math.
Amy: Maybe the math was too bubbly for him.
Sheldon: You think you're doing science by cutting up that brain? They could do the same thing at any Quiznos. And they'd offer to toast it for me, too.

Amy: Okay, smart guy. I'm about to remove the locus coeruleus, which is incredibly delicate work. Have at it.
Sheldon: All right. I'm no stranger to a little gray matter. Locus coeruleus. Locus coeruleus.
Amy: You're getting warmer, it is, indeed, in the brain. Hope your hands are steady. It's the width of a single hair. But this is just biology, so I'm sure it's no problem for a genius like you.
Sheldon: It's not. I'll have you know, in the field of physics, we work with particles so small, they make fat jokes about the locus coeruleus, i.e., when your locus coeruleus sits around the house, it sits around the house.

Sheldon: Does a locus coeruleus normally bleed that much?
Amy: No. But your thumb does.
Sheldon: Oh, dear. (Faints)

Howard: What happened to your thumb?
Sheldon: You know, I have ten fingers and ten toes. If I tell you a story about each one of them, we'll be here all day, let's just move on.